In modern manufacturing processes, quality of the final product has become of increasing concern. The buying public, whether it be industrial buyers or ultimate consumers, has become very quality aware and will reject products which do not meet the exacting standards maintained by the ever more sophisticated buying public. This is particularly true in the automotive field.
Automotive products make extensive use of sheet metal stampings. Such stampings form the exterior body of the vehicle as well as numerous body panels provided behind the exterior surface. Purchasers of vehicles, whether the vehicles are automobiles or light trucks, are highly critical of the total assembly. "Fit and finish" are major concerns and strongly affect the public's decision relative to the purchase of a car or light truck. In addition to perceived quality, structural quality is also very necessary in order to ensure that the vehicle performs and is durable in accordance with the desired standards. This applies to sheet metal parts which may not be seen by the public but which, if not properly made and assembled, will ultimately effect the overall quality of a vehicle and form a basis for customer's making decisions whether or not to repeat a purchase from a particular automotive company.
Stamped sheet metal parts may be improved in the basic manufacturing process in order to result in increased quality. Improved stampings have been obtained with parts made by multiple stamping dies wherein cumulative bench mark indicia are impressed on the parts. A multiple station stamping press line is provided with die sets having special bottoming markers which imprint bench mark indicia on the part at each stamping station to provide a readout on the finally stamped part that reveals the accuracy of stamping at each station and identifies any stations that is not stamping to specifications.
While repeatable stampings of high quality have been provided using the above-identified method, component assemblies of mating stamped parts even when properly made often do not properly match with one another in the assembly to meet standards needed for the desired quality production. To achieve such goals, the present invention provides for the marking of mating stamped parts with bench mark indicia that interrelate with one another. With the parts having bench marking that relate to one another, the parts can, by using the bench marks, be positioned relative to each other and the dimensional quality can be verified by visually examining the relative positions of the bench marks.
It is a feature, object and advantage of this invention to provide new and improved press line stamping procedures and assembly techniques. Preferably, each stamping is formed by a die set having bottoming markers that apply bench marks to the parts being stamped that relate to other parts being stamped so that parts can be matched to one another by the bench marks thus optimizing quality of an assembly of the parts.
These and other features, objects and advantages of this invention will become more apparent from the drawings and the following written matter: